Rotary shuttle for sewing machines

ABSTRACT

A rotary shuttle for a sewing machine is made of two plates which are press-formed to have dished wall portions and partcircular flanges circumferentially abutting each other, and being brazed or welded together. The plates are cut out to form a recess for the passage of a sewing needle, and a hook for catching a thread.

I United States Patent 11 1 3,705,562 Hanyu et al. 1 Dec. 12, 1972 [s41 ROTARY SHUTTLE FOR SEWING 3,016,033 1/1962 11mm ..1112/232 MACHINES 3,146,744 9/1964 Bradshaw ..112/232 [72] Inventors: Susumu Hanyu; Takashi Amano, FOREIGN PATENTS OR APPLICATIONS both of Japan 357,474 3/1922 Germany ..112/232 [73] Assignee: Janome Sewing Machine Co. Ltd., 423,991 1/1926 Germany ..112/231 Tokyo Japan Primary Examiner-Alfred R. Guest [22] Filed: April 27, 1971 Attorney-Michael S. Striker A rotary shuttle for a sewing machine is made of two Foreign Application Prifirlty Data plates which are press-formed to have dished wall portions and part-circular flanges circumferentially Aprll 28, 1970 Japan ..45/35952 abutting each other, and being brazed or e ded together. The plates are cut out to form a recess for [52] US. Cl. ..112/232 the passage of a Sewing needue, and a hook for [51] Int. Cl. ..D05b 57/10 catching a thread [58] Field of Search ..112/231, 232,181,185, 228,

112/229, 230 9 Claims, 7 Drawing Flgures [56] References Cited UNITED STATES PATENTS Hohmann ..112/231 PATENTEnnEc12 I972 SHEET 1 OF 3 FIG.2

PATENTED 12 I97? 3. 705. 562

SHEET 3 BF 3 ROTARY SHUTTLE FOR SEWING MACHINES BACKGROUND OF THE INVENTION It is known to provide sewing machines with rotary shuttles for catching a thread loop and for enlarging the same. It is necessary to manufacture a rotary shuttle with great precision to assure even rotation in the shuttle holder, and reliably guiding a thread loop. In accordance with the prior art, rotary shuttles are made by cutting, shaping and like machining operation of a tempered material, or by founding a deformable material in a mold. For cutting and machining a rotary shuttle, more than 21 operational steps are required, and moreover, highly skilled operators have to carry out the necessary precision work. Since there are losses due to cutting, which causes dust and scrapedoff particles, a greater amount of expensive material is required. Furthermore, cutting operations cause burrs and grates on the shuttle so that the same will vibrate or oscillate when rotating at high speed, having the disadvantage of great wear due to abrasion, and also of a noisy operation.

When a shuttle is made of precision casting, special material has to be used, and the making of the casting die is very expensive so that the price per unit is fairly high, so that the method of casting rotary shuttles has not been actually put into practice.

It has been proposed to use plates for making a rotary shuttle, but is is difficult to provide in this manner a reliably operating shuttle hook, and furthermore, the shuttle hook requires a joint which frequently creates a crack which renders the shuttle inoperative.

SUMMARY OF THE INVENTION It is one object of the invention to make a rotary shuttle for a sewing machine by sheet metal processing operations.

The main object of the invention is to produce a rotary shuttle which is suitable for mass production.

ln accordance with the invention, sheet metal parts are deformed by a press, so that cutting operations required for the shuttles of the prior art, are almost completely eliminated. Consequently the production is increased several times as compared with the prior art. The required shape of the shuttle can be easily produced by press forming, and only few trimming, cutting and grinding operations are required for finishing the shuttle of the invention. The most difficult steps of the prior art need not be carried out, and the shuttle can be manufactured by less skilled operators. Particularly, difficult manual operations are almost completely eliminated, and the production of the shuttle can be carried out by machines.

Another object of the invention is to reduce losses of material during the manufacture of the shuttle.

Since the prior art requires more than operational steps, evidently high losses of material occur. In the present invention, steel plates are stamped out of sheet material, and subjected to press forming to obtain such a shape that only few cutting and drilling operations are required for the finishing of the shuttle, and accordingly, the losses of material are low. As compared with the prior art, the loss of material is reduced by one-third.

Another object of the invention is to provide a rotary shuttle of great mechanical strength and accurately performing the required functions, such as catching a thread and opening a thread loop.

Irrespective of the fact that the shuttle of the invention is made of steel plates, and by a few operations, the present invention provides a mechanically strong shuttle since flanges of the steel plates are placed in abutting positions. and brazed or welded to form a strong arcuate rib along a plane of symmetry of the shuttle and serving for engaging the race of the shuttle holder. The reinforcedpreferably circular rib extends along the periphery of the finished shuttle, and provides structural rigidity which is superior to shuttles of the prior art.

It is well known that a rolled steel plate has a grain composition which is stronger than a out part. The hook of the rotary shuttle of the invention is formed at one end of the rigid flange so that no cracks form, and no breakage takes place.

Another object of the invention is to provide a lightweight shuttle. The rotary shuttle of the invention is hollow for mounting a bobbin in the cavity of the shuttle, and has other required parts at the periphery or outside thereof. When a rotary shuttle according to the prior art is cut in many operations, grates and burrs inevitably remain on the finished shuttle so that the weight of the same is unnecessarily increased. Since in accordance with the invention, steel plates are press formed, all parts of the finished shuttle are of uniform thickness, and there will be no grates or burrs. As a result, the shuttle of the invention is lighter than shuttles of the prior art, by about 10 to 20 percent compared with shuttles made by cutting operations.

Another object of the invention is to provide a rotary shuttle which reliably operates in a standard sewing machine.

The rotary shuttle of the invention has a low weight, and will rotate smoothly without vibration or noise.

Although the peripheral rib of the shuttle consists of two abutting flanges, it does not detrimentally effect the inertial rotation of the shuttle.

The shuttle of the invention is made of a main body and a front body, both of which have flanges and dished portions on both sides of the rib of the shuttle, so that the shuttle can take and enlarge a thread loop, and release it smoothly. The hook of the shuttle of the invention is rigid enough to perform its function indefinitely.

The rotary shuttle according to one embodiment of the invention comprises a main body having a central wall portion through which the axis of the shuttle passes, a first dished wall portion on one side of the central wall portion continuing the same, a peripheral hook portion, and an arcuate flange projecting parallel to the axis in one direction from a part of the periphery of the first dished wall portion; and a front body having a second dished wall portion confronting the first dished wall portion, and an arcuate second flange projecting parallel to the axis in the opposite direction from a part of the periphery of the second dished wall portion.

The first and second flanges have first and second circumferential surfaces abutting each other and bonded together, for example by brazing or welding, to form an arcuate, preferably part-circular rim along and between the first and second dished wall portions so that the same form a cavity for a bobbin case, while the outer surfaces of the same can guide and enlarge a threaded loop. A bobbin case supporting pin is secured to the central portion of the main body, projecting from the same through the cavity in the shuttle. The front body is formed with a cutout slot for the passage of the needle.

The main body and the front body are first and second plates, preferably steel plates punched out of sheet material, and then shaped in a press to form the first and second flanges and the first and second dished wall portions, respectively. The first flange has a cutout adjacent the hook, which is formed of a portion of the first flange of the main body.

The novel features which are considered as a characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a elevation illustrating a pair of steel plate blanks of which the main body and front body of the rotary shuttle are, respectively, formed;

FIG. 2 is a front elevation having portions A and B respectively illustrating the steel plate blanks of FIG. 1 after a forming operation in a press;

FIG. 3 is a rear view having portions A and B illustrating the steel plate blanks of FIG. 1 after the forming operation in the press;

FIG. 4 is a plan view having portions A and B illustrating the main body and front body of a shuttle according to the invention after cutting operations;

FIG. 5 is a side view, partially in section, illustrating a shuttle assembled of the parts shown in FIG. 4;

FIG. 6 is a perspective view of the assembled shuttle shown in FIG. 5; and

FIG. 7 is an exploded perspective view illustrating the main body and front body of the shuttle separated from each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and particularly to FIG. 1, a first steel plate blank A is about l.2 mm. thick, and a steel plate blank B, whose thickness is about 1 mm., are shown. Blanks A and B are punched out of sheet material.

Blank A has a semi-circular peripheral portion A and has on a projection A adjacent the circular portion A separated by a recess A, from another projection A, which is separated by a recess A; from a central rounded projecting portion A The blank plate B is substantially crescent-shaped, and has a part-circular peripheral edge B a curved inner edge B and a projection B formed by the inner edge B, and another transverse curved edge B The punched out blank plate A, and the punched out blank plate B are subjected to independent press forming operations to obtain the shapes shown in FIGS. 2 and 3 at (A) and (B), respectively. A main body 10 is formed by press forming the blank A, and a front body is formed by press forming the blank B.

Main body 10 has a flat central portion 13 into which a bore 16 is drilled later on. A dished wall portion 14 continues one side of the flat central portion 13, and has a substantially frusto-conical shape, as best seen in FIG. 4. A part circular flange 12 has a center coinciding with the center of the bore 16, and projects parallel to an axis which is perpendicular to the flat portion 13. At one end of flange 12, an outwardly projecting portion is formed which includes portions 15a and 15b which are slanted to the flange 12. The projecting portion 15 is connected with an arcuate shoulder 12b of constant radial width located between flange 12 and the dished wall portion 14, as best seen in FIGS. 4 and 5. Another flange portion 12a projects from flange 12 in a direction opposite to the projecting portion 15, and is formed of edge portions of the projections A A and of the recess A of blank A shown in FIG. 1. The projecting portion 15 is connected with flange 12a by the portion 15b. The flange 12a is of trapezoidal shape in the plan views of FIGS. 2 and 3, and has an end portion 18 formed of blank projection A and a tongue 19 formed of projecting blank portion A,.

The front body 20 has after press forming the shape shown in FIGS. 2 and 3 in views (B). The circular peripheral edge B of blank B shown in FIG. 1, is deformed into a part-circular flange 22 which matches flange 12 of main body 10, so that the main body 10 and front body 20 can be assembled in the position shown in FIG. 5 in which the outer circular surface of flange 22 abuts the inner circular surface of flange 12 and forms together with the same, after brazing or welding, a part-circular rib 40.

Flange 22 has an inner surface connected at one end with a slanted wall portion 24 which is an extension of an arcuate shoulder 23 provided between the dished wall portion 24 and flange 22. The outer surface of the dished wall portion 24 has its highest point at the projecting portion 27, which is formed of projection B, of blank plate B. The arcuate shoulder 23 is enlarged to a substantially triangular shape adjacent the blank projection 8,, as clearly shown in FIGS. 2 and 3.

The triangular extension of shoulder 23 is connected with the dished wall 24 by a flat wall 25 which is substantially perpendicular to the dished wall portion 24, and to the extension of shoulder 23.

Shoulder 23 of front body 20 is narrower than shoulder 12b of the main body 10. The part-circular shoulder 12b of the main body 10, and the part-circular shoulder 23 of the front body 20, together with the part-circular flanges l2 and 22 form the peripheral rib 40 shown in FIG. 5 which supports the assembled shuttle in the race of the shuttle holder, not shown. The shoulders 12b and 23 reinforce the main body 10 and front body 20, since the rim of the inner flange 22 of front body 20 abuts the inner surface of the shoulder 12b adjacent flange 12 of the main body 10. Due to the fitting of flange 22 into flange 12, the two parts 10 and 20 of the shuttle can be easily assembled in the position shown in FIG. 5, whereupon flanges l2 and 22 are bonded together, preferably by brazing or welding.

Before the two parts 10 and 20 of the shuttle are assembled, certain cutting operations are carried out as shown by thin phantom lines in FIGS. 2 and 3. As noted above, the central portion 13 is provided with a hole 16 concentric with the circular flange 12. The outwardly projecting portion 15 is cut off along a cutting line 17 extending along the outer circumference of flange 12 of main body 10. The cutout 18a formedin this manner in flange 12, is best seen in FIG. 6. The flange portion 12a is formed in such a manner that a sharppoint 18 forming the hook of the shuttle remains, as best seen in FIGS. 4, 6 and 7.

After the projecting portion 15 has been cut out of flange 12 of main body 10, hook 18 is bounded by the surface 17a shown in FIG. 4.

The triangular portion 21 of the front body 20, shown in FIGS. 2 and 3, is cut out to form a slot 26 0f 2.5 mm. to 3 mm. width betweenflange 22 and projecting portion 27, the finished slot 26 being best seen in FIG. 4 in which slot 26 is shown to be bounded by two projections 27 and 28 formed of blank portion B, and the end of the flange 22, respectively. Projections 27 and 28 are located at different levels in relation to the axis of the shuttle and to the center of front body 20.

FIG. 4 shows the parts and 20 of the almost complete shuttle. The projecting portion including part 150 shown in FIGS. 2 and 3 at (A) is cut off and leaves a trapezoidal edge surface extending between the cut off flange 12, and the flange part 12a, best seen in FIG. 2 (A), and formed on the recessed edgeA, of the blank plate A in FIG. 1. The flange portion 120 is connected with the hook point 18 and reinforces the same, while the other portion of flange 12a, which extends along projection A, of blank plate A shown in FIG. 1, projects in the form of a tongue 19.

The part-circular shoulder 12b between flange 12 and the dished wall 14 of the main body 10 has an inner surface on which the circular rim of flange 22 abuts in the assembled condition shown in FIG. 5. Front body is substantially crescent-shaped, as shown in FIGS. 6 and 7, but one end portion of the same is divided into the end portion 24a of the dished portion 24, bounded by the inner edge 29, and the end portion 28 of the flange 22, as best seen in FIG. 7. End portion 27a is also bounded by the edge 25, which defines with the end portion 28 of flange 22, the open slot 26 in which the needle of the sewing machine reciprocates.

Tongue 27 of front body 20 is a counterpart of the tongue 19 of the main body 10 and continues the edge 29 of the dished wall portion 24. Edge 29 is curved and bounds recess 26 for drawing the lower thread supplied from the bobbin in the shuttle. The outer surfaces of main body 10 and front body 20 are finished by grinding and polishing operations.

As best seen in FIGS. 5 and 7, a pin 31 is provided for mounting a bobbin case, not shown. Pin 31 has an end portion 36 inserted into the bore 16 of the central wall portion 13 of main body 10, a flange 35 abutting the same, a shaft portion 32, a neck portion 33 and a head 34 projecting across the crescent-shaped dished portion 24 of front body 20.

The main body 10 and the front body 20 are assembled in the position shown in FIGS. 5 and 6 with the outer surface of flange 22 abutting on the inner surface of flange 12 of the main body 10. The inner surface of the circular planar shoulder 12b is in contact with the edge of flange 22 since flanges 12 and 22 extend both at right angles to shoulder 12b. The abutting flanges 12 and 22 are brazed or welded to each other so that the part-circular rim 40 assures rigidity of the shuttle.

The outerperipheralsurface of the assembled rotary shuttle, and the lateral surfaces thereof, are, if necessary ground to increase the precision of the shuttle, whereupon the surfaces are carburizedand tempered to increase the hardness of the steel. After these operations, the shuttle is coated with a suitable finishing material.

As explained above, the two parts 10 and 20 of the shuttle are press formed, and are brazed or welded, or bounded in any other manner to each other to form the rotary shuttle. The rib 40 formed along the circumference of the shuttle, is very rigid so that the shuttle smoothly rotates in the race of the shuttle holder, not shown.

Due tothe cutting of a trapezoidal edge forming the recess 18a, the hook point is precisely formed and capable of taking up the thread loop. Due to the fact that only a few cutting operations, leaving almost no grates or burrs are carried out, the shuttle is of lightweight, and noise caused by vibration at high speed rotation is eliminated so that the loop forming and stitching operations are reliably carried out. Also, very little metal is lost during the manufacture of the shuttle, due to simplification of the shuttle of the present invention.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of rotary shuttle for sewing machines differing from the types described above.

While the invention has been illustrated and described as embodied in a rotary shuttle composed of two parts shaped by press forming of blank plates stamped out of sheet material, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting; features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended. within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. For use with a sewing machine, a rotary shuttle having an axis, and comprising: a main body having a central wall portion through which said axis passes, a first dished wall portion on one side of said central wall portion continuing the same, a peripheral hook portion, and an arcuate first flange projecting parallel to said axis in one direction from a part of the periphery of said first dished wall portion; and a front body having a second dished wall portion confronting said first dished wall portion, and an arcuate second flange projecting parallel to said axis in a direction opposite to said one direction from a part of the periphery of said second dished wall portion, said first and second flanges having first and second circumferential surfaces abutting each other and being bonded together to form an arcuate rim along and between said first and second dished wall portions so that the same form a cavity for a bobbin case, and have outer surfaces adapted to guide and enlarge a thread loop.

2. A rotary shuttle as claimed in claim 1 comprising a pin secured to said central portion and projecting from the same in said one direction concentric with said axis for supporting a bobbin case for rotation about said axis.

3. A rotary shuttle as claimed in claim 1 wherein said main body includes a supporting wall portion having a tongue located on said first flange for supporting and reinforcing said hook.

4. A rotary shuttle as claimed in claim 1 wherein said front body is formed with a slot for passage of a needle and located adjacent said second flange; and a pair of projections defining said slot and being spaced in axial direction.

5. A rotary shuttle as claimed in claim 1 wherein said main body has a shoulder located between said first dished wall portion and said first flange and being perpendicular to the latter; wherein said second flange is located within said first flange; and wherein the edge of said second flange abuts the inner surface of said shoulder.

6. A rotary shuttle as claimed in claim 5 wherein said front body has a narrow shoulder between said second dished portion and said second flange and being perpendicular to said second flange.

7. A rotary shuttle as claimed in claim 1 wherein said main body and said front body are first and second plates, each of said first and second plates being of uniform thickness. I

8. A rotary shuttle as claimed in claim 7 wherein said first flange has a cutout adjacent said hook; and wherein said hook is formed of a portion of said first flange.

9. A rotary shuttle as claimed in claim 1 wherein said first and second flanges extend along circles concentric with said axis.

UNITED STATES PATENT OFFHIE @ERHWQATE M QREQMQN Patent No. 3,705,562 Dated December 12, 1972 Inventor(s) Susumu HanYu 612 all,

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On. the cover sheet the illustrated drawing should appear shmm below:

Cancel 1-3 7155a'iawfiigan'a insert sheets 1-4 as shown on the attached sheets.

Signed and sealed this 5th day of February 1974.

@SEAL) Attest:

EDWARD MQFLETCHERJR. RENE D, TEG'JgMEYER Attesting Officer Acting Commlssloner .of Patent:

FORM PO =1050 HO GS) USCOMM-DC 60316P69 us. GOVERNMENT rmurnus OFFICE lass o-au-su. 

1. For use with a sewing machine, a rotary shuttle having an axis, and comprising: a main body having a central wall portion through which said axis passes, a first dished wall portion on one side of said central wall portion continuing the same, a peripheral hook portion, and an arcuate first flange projecting parallel to said axis in one direction from a part of the periphery of said first dished wall portion; and a front body having a second dished wall portion confronting said first dished wall portion, and an arcuate second flange projecting parallel to said axis in a direction opposite to said one direction from a part of the periphery of said second dished wall portion, said first and second flanges having first and second circumferential surfaces abutting each other and being bonded together to form an arcuate rim along and between said first and second dished wall portions so that the same form a cavity for a bobbin case, and have outer surfaces adapted to guide and enlarge a thread loop.
 2. A rotary shuttle as claimed in claim 1 comprising a pin secured to said central portion and projecting from the same in said one direction concentric with said axis for supporting a bobbin case for rotation about said axis.
 3. A rotary shuttle as claimed in claim 1 wherein said main body includes a supporting wall portion having a tongue located on said first flange for supporting and reinforcing said hook.
 4. A rotary shuttle as claimed in claim 1 wherein said front body is formed with a slot for passage of a needle and located adjacent said second flange; and a pair of projections defining said slot and being spaced in axial direction.
 5. A rotary shuttle as claimed in claim 1 wherein said main body has a shoulder located between said first dished wall portion and said first flange and being perpendicular to the latter; wherein said second flange is located within said first flange; and wherein the edge of said second flange abuts the inner surface of said shoulder.
 6. A rotary shuttle as claimed in claim 5 wherein said front body has a narrow shoulder between said second dished portion and said second flange and being perpendicular to said second flange.
 7. A rotary shuttle as claimed in claim 1 wherein said main body and said front body are first and second plates, each of said first and second plates being of uniform thickness.
 8. A rotary shuttle as claimed in claim 7 wherein said first flange has a cutout adjacent said hook; and wherein said hook is formed of a portion of said first flange.
 9. A rotary shuttle as claimed in claim 1 wherein said first and second flanges extend along circles concentric with said axis. 